Move rapidly (4)
(Other definitions for hurtle that I've seen before include "Dash, move rapidly" , "Move at great speed" , "Career (along)" , "Rush headlong" , "Proceed quickly and noisily" .)
'move rapidly' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for dart that I've seen before include "Small spiked missile thrown in sport" , "Arrow; dash" , "Run suddenly" , "Slender pointed missile" , "Small narrow pointed missile" .)
'move rapidly' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for whizz that I've seen before include "Clever clogs - move fast" , "Move rapidly (colloq.)" , "Loud humming - extremely skilful person" , "Move rapidly - make hissing sound" , "Skilled person (colloq.)" .)